Elevated sea surface temperatures in the equatorial Pacific, characteristic of El Nino have been present for months, but National Weather Service climate science and services manager Rick Thoman says until recently, there’s been no link to the atmosphere.

“That’s what’s changed. The atmosphere is now starting to respond in the more typical El Nino fashion.”

Thoman says that means consistent deep tropical thunderstorm activity along the equator from southwest of Hawaii east to South America, but summer impacts to North America are generally not very strong.

“It’s really when we start to get into the autumn the big tropical thunderstorms can start to affect Jet Stream flow and potentially our weather.”

That said, Thoman expects El Nino will extend already warmer than normal sea temperatures along the west coast, and Alaska. As far as likely weather impacts in Alaska next winter, Thoman points to general trends.

“El Nino winters for Alaska tend to be relatively mild. Precipitation tends to be above normal along the Gulf Coast, but the Interior tends to tilt dry.”

Thoman adds that the impact of El Nino hinges on its strength, something meteorologists don’t have a handle on yet.